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/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chsys.c
* @brief System related code.
*
* @addtogroup system
* @details System related APIs and services:
* - Initialization.
* - Locks.
* - Interrupt Handling.
* - Power Management.
* - Abnormal Termination.
* - Realtime counter.
* .
* @{
*/
#include "ch.h"
/*===========================================================================*/
/* Module exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local functions. */
/*===========================================================================*/
#if !CH_CFG_NO_IDLE_THREAD || defined(__DOXYGEN__)
/**
* @brief This function implements the idle thread infinite loop.
* @details The function puts the processor in the lowest power mode capable
* to serve interrupts.<br>
* The priority is internally set to the minimum system value so
* that this thread is executed only if there are no other ready
* threads in the system.
*
* @param[in] p the thread parameter, unused in this scenario
*/
static void _idle_thread(void *p) {
(void)p;
chRegSetThreadName("idle");
while (true) {
port_wait_for_interrupt();
CH_CFG_IDLE_LOOP_HOOK();
}
}
#endif /* CH_CFG_NO_IDLE_THREAD */
/*===========================================================================*/
/* Module exported functions. */
/*===========================================================================*/
/**
* @brief ChibiOS/RT initialization.
* @details After executing this function the current instructions stream
* becomes the main thread.
* @pre Interrupts must disabled before invoking this function.
* @post The main thread is created with priority @p NORMALPRIO and
* interrupts are enabled.
*
* @special
*/
void chSysInit(void) {
#if CH_DBG_ENABLE_STACK_CHECK
extern stkalign_t __main_thread_stack_base__;
#endif
port_init();
_scheduler_init();
_vt_init();
#if CH_CFG_USE_TM
_tm_init();
#endif
#if CH_CFG_USE_MEMCORE
_core_init();
#endif
#if CH_CFG_USE_HEAP
_heap_init();
#endif
#if CH_DBG_STATISTICS
_stats_init();
#endif
#if CH_DBG_ENABLE_TRACE
_dbg_trace_init();
#endif
#if !CH_CFG_NO_IDLE_THREAD
/* Now this instructions flow becomes the main thread.*/
setcurrp(_thread_init(&ch.mainthread, NORMALPRIO));
#else
/* Now this instructions flow becomes the idle thread.*/
setcurrp(_thread_init(&ch.mainthread, IDLEPRIO));
#endif
currp->p_state = CH_STATE_CURRENT;
#if CH_DBG_ENABLE_STACK_CHECK
/* This is a special case because the main thread thread_t structure is not
adjacent to its stack area.*/
currp->p_stklimit = &__main_thread_stack_base__;
#endif
chSysEnable();
/* Note, &ch_debug points to the string "main" if the registry is
active, else the parameter is ignored.*/
chRegSetThreadName((const char *)&ch_debug);
#if !CH_CFG_NO_IDLE_THREAD
/* This thread has the lowest priority in the system, its role is just to
serve interrupts in its context while keeping the lowest energy saving
mode compatible with the system status.*/
chThdCreateStatic(ch.idle_thread_wa, sizeof(ch.idle_thread_wa), IDLEPRIO,
(tfunc_t)_idle_thread, NULL);
#endif
}
/**
* @brief Halts the system.
* @details This function is invoked by the operating system when an
* unrecoverable error is detected, for example because a programming
* error in the application code that triggers an assertion while
* in debug mode.
* @note Can be invoked from any system state.
*
* @param[in] reason pointer to an error string
*
* @special
*/
void chSysHalt(const char *reason) {
port_disable();
#if defined(CH_CFG_SYSTEM_HALT_HOOK) || defined(__DOXYGEN__)
CH_CFG_SYSTEM_HALT_HOOK(reason);
#endif
/* Pointing to the passed message.*/
ch.dbg.panic_msg = reason;
/* Harmless infinite loop.*/
while (true)
;
}
/**
* @brief Handles time ticks for round robin preemption and timer increments.
* @details Decrements the remaining time quantum of the running thread
* and preempts it when the quantum is used up. Increments system
* time and manages the timers.
* @note The frequency of the timer determines the system tick granularity
* and, together with the @p CH_CFG_TIME_QUANTUM macro, the round robin
* interval.
*
* @iclass
*/
void chSysTimerHandlerI(void) {
chDbgCheckClassI();
#if CH_CFG_TIME_QUANTUM > 0
/* Running thread has not used up quantum yet? */
if (currp->p_preempt > 0)
/* Decrement remaining quantum.*/
currp->p_preempt--;
#endif
#if CH_DBG_THREADS_PROFILING
currp->p_time++;
#endif
chVTDoTickI();
#if defined(CH_CFG_SYSTEM_TICK_HOOK)
CH_CFG_SYSTEM_TICK_HOOK();
#endif
}
/**
* @brief Returns the execution status and enters a critical zone.
* @details This functions enters into a critical zone and can be called
* from any context. Because its flexibility it is less efficient
* than @p chSysLock() which is preferable when the calling context
* is known.
* @post The system is in a critical zone.
*
* @return The previous system status, the encoding of this
* status word is architecture-dependent and opaque.
*
* @xclass
*/
syssts_t chSysGetStatusAndLockX(void) {
syssts_t sts = port_get_irq_status();
if (port_irq_enabled(sts)) {
if (port_is_isr_context())
chSysLockFromISR();
else
chSysLock();
}
return sts;
}
/**
* @brief Restores the specified execution status and leaves a critical zone.
* @note A call to @p chSchRescheduleS() is automatically performed
* if exiting the critical zone and if not in ISR context.
*
* @param[in] sts the system status to be restored.
*
* @xclass
*/
void chSysRestoreStatusX(syssts_t sts) {
if (port_irq_enabled(sts)) {
if (port_is_isr_context())
chSysUnlockFromISR();
else {
chSchRescheduleS();
chSysUnlock();
}
}
}
#if PORT_SUPPORTS_RT || defined(__DOXYGEN__)
/**
* @brief Realtime window test.
* @details This function verifies if the current realtime counter value
* lies within the specified range or not. The test takes care
* of the realtime counter wrapping to zero on overflow.
* @note When start==end then the function returns always true because the
* whole time range is specified.
* @note This function is only available if the port layer supports the
* option @p PORT_SUPPORTS_RT.
*
* @param[in] cnt the counter value to be tested
* @param[in] start the start of the time window (inclusive)
* @param[in] end the end of the time window (non inclusive)
* @retval true current time within the specified time window.
* @retval false current time not within the specified time window.
*
* @xclass
*/
bool chSysIsCounterWithinX(rtcnt_t cnt, rtcnt_t start, rtcnt_t end) {
return end > start ? (cnt >= start) && (cnt < end) :
(cnt >= start) || (cnt < end);
}
/**
* @brief Polled delay.
* @note The real delay is always few cycles in excess of the specified
* value.
* @note This function is only available if the port layer supports the
* option @p PORT_SUPPORTS_RT.
*
* @param[in] cycles number of cycles
*
* @xclass
*/
void chSysPolledDelayX(rtcnt_t cycles) {
rtcnt_t start = chSysGetRealtimeCounterX();
rtcnt_t end = start + cycles;
while (chSysIsCounterWithinX(chSysGetRealtimeCounterX(), start, end))
;
}
#endif /* PORT_SUPPORTS_RT */
/** @} */
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